(a) Field
The invention relates to a flexible display device. More particularly, the invention relates to a flexible organic light emitting diode display including an organic light emitting element.
(b) Description of the Related Art
An organic light emitting diode display is a self-light emitting display that displays an image by using an organic light emitting diode that emits light. The organic light emitting diode display differs from a liquid crystal display as not including a separate light source, and having relatively small thickness and weight. Furthermore, as the organic light emitting diode display involves high quality characteristics such as low power consumption, high luminance and short response time, the organic light emitting diode display is spotlighted as a next generation display device for portable electronic appliances.
The organic light emitting element includes two electrodes and an emitting layer located therebetween, and excitons are generated by combining electrons provided from one of the two electrodes and holes provided from the other electrode at the emitting layer. Energy is output from the excitons when a ground state thereof is reached, to thereby emit light.
It is important for the organic light emitting element to have increased luminous efficiency and to simultaneously have an improved life-span.
To increase the life-span of the organic light emitting element, a structure of a plurality of deposited charge auxiliary layers such as an emission layer, a hole injection layer, and an electron injection layer to increase the magnitude of luminance for a current by two times or three times has been developed.